1. Field of the Invention
The present invention generally relates optical sensors, and more particularly, the present invention relates to an optical sensor device in which an ultraviolet ray sensor and a visible light sensor are integrated into a single chip.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 7-162024 discloses an example of ultraviolet ray sensor (UV sensor) having a structure in which a light receiving device is formed in a semiconductor layer on an insulating substrate. The sensitivity of the light receiving device is primarily in the ultraviolet spectrum.
In the meantime, Japanese Patent Application Laid-Open No. 2004-006694 discloses an example of a visible light sensor. In this publication, a light receiving device is described having a structure in which an n-type region is formed within a p-type silicon substrate and a p-type region is formed within the n-type region, to thereby form two photodiodes in a vertical direction. In the light receiving device, outputs from these two photodiodes are processed to realize a visible light sensor. Such is also referred to as an intensity sensor since it measures an intensity of the visible light.
Products having the functionality of both an ultraviolet ray sensor and a visible light sensor incorporate two separately fabricated semiconductor chips into a single package, i.e., one chip for the UV sensor and another chip for the visible light sensor.